Answer:
B
Explanation:
They come from other Rocks or living things such as bones,leaves,stems, etc.
 
        
             
        
        
        
Answer:
A genetic chain is something your grandparents passed on to your parents, and your parents passed it on to you, and so forth!
Explanation:
 
        
             
        
        
        
Answer:
आप क्या कह रहे हैं भाई मुझे समझ में नहीं आया क्या यह सवाल है 
 
        
             
        
        
        
The answer is B 
Hope this helps
        
             
        
        
        
Answer:
Have different numbers of neutrons
Explanation:
Isotopes of an element have different atomic numbers because thy differ in neutron number even though proton number remains the same across the isotopes. The mass number is the summation of the proton and neutron number. Phosphorus has approximately 23 isotopes whose mass number range between 25 and 47. Only ³¹P is stable.